Difference between S08JS16CWJ and S08JS16LCWJ to build the USBDM ?

[Joel69003]

Hello all, particularly PGO if you see this message,

I have build a new USBDM but it is not working at all whereas all my previous ones was OK. I have check hardware, PCB, soldering, everything is fine. This is an USBDM with S08JS16 µC, when connected to the host computer the first time it should (or possibility to force with BLMS pin) enter in bootloader mode. However, the host computer is not detecting it.. :-( it seems the USB is not starting : the internal USB regulator output available on pin 17 (SOIC20 package) is only 0.2 to 1.6V instead of 3.3V... I have uploaded the USBDM firmware in it using an other USBDM (ok), but after that USB is still not working, and host computer does not detect the device.

All my previous USBDM was build with S08JS16CWJ devices. This new one has S08JS16LCWJ. Is there any known problems with it ?

Thanks for reading and for your feedbacks !

Regards,

Joel Guittet

[Joel69003]

In the datasheet I have notice the following comments regarding JS16L device:

The only difference between MC9S08JS16/MC9S08JS8 and MC9S08JS16L/MC9S08JS8L is that MC9S08JS16 and MC9S08JS8 support USB bootloader function with voltage above 3.9 V while MC9S08JS16L and MC9S08JS8L support USB bootloader function at 3.3 V.

Disable internal USB voltage regulator and apply 3.3 V to the VUSB33 pin when using MC9S08JS16L and MC9S08JS8L for the USB bootloader function.

and tried to supply VUSB33 pin with 3.3V but don't seems to change anything... Does this note in the datasheet indicate that the JS16L device can be supplied at 3.3V only (and no more) ?

[pgo]

Hi Guittet,

I have never used the 'L' version so I have no experience.

Carefully searching the chip manual only shows the single reference you have given above.  It is somewhat ambiguous but I find it unlikely that it is meant to be a requirement for the bootloader function i.e. I would expect it to be usable at other voltages without having to disable the regulator - After all how can you do this with a blank chip?

The Data sheet (where I would expect electrical differences to be highlighted) has no significant references to the 'L' device.  They are treated identically.

I can offer no suggestions why it would not work.  I can only suggest trying another chip to see if this is a consistent problem with the 'L' devices.

bye

[Joel69003]

Hello PGO,

Thanks for writing, this confirmed maybe it is not working with the 'L' version of the µC. I have checked again the datasheet too and made various tests to make the USB working, but not successfully. I don't know why, as you said the datasheet is ambiguous.

So for any people seeing this post, it is highly recommend to use S08JS16CWJ device, not S08JS16LCWJ.

Regards,

Joel Guittet